The effects of chemical and physical penetration enhancers on the percutaneous permeation of lidocaine through equine skin.
Authors: Stahl Jessica, Kietzmann Manfred
Journal: BMC veterinary research
Summary
# Editorial Summary: Percutaneous Penetration Enhancers for Equine Lidocaine Delivery Delivering local anaesthetics effectively through equine skin presents a significant clinical challenge, prompting Stahl and Kietzmann to investigate both chemical solvents and microneedle technology as potential enhancement strategies for transdermal lidocaine permeation. Using excised thoracic skin from six Warmblood horses mounted in Franz-type diffusion cells, the researchers tested six different vehicles (ranging from phosphate-buffered saline to dimethylsulfoxide and alcohol-based solutions) alongside microneedle pretreatment at varying depths to quantify lidocaine penetration via high-performance liquid chromatography. The chemical enhancers demonstrated variable efficacy, with certain formulations substantially improving drug permeation compared to basic PBS controls, whilst microneedle pretreatment provided an additional physical enhancement pathway, though the specific permeation values warrant review of the full manuscript for clinical translation. These findings offer farriers, veterinarians, and physiotherapists evidence-based options for optimising topical lidocaine delivery in equine practice, potentially reducing the number of needle injections required or improving anaesthetic efficacy for superficial procedures. Understanding which vehicle or physical approach works best could meaningfully improve animal welfare during routine therapeutic and diagnostic interventions.
Read the full abstract on PubMed
Practical Takeaways
- •DMSO or isopropylalcohol-based formulations may improve penetration of topical lidocaine preparations for local anesthetic delivery in horses
- •Microneedle application prior to topical anesthetic administration could enhance drug delivery, though clinical safety and efficacy require further investigation
- •Formulation choice matters significantly—standard PBS vehicles provide minimal enhancement compared to alcohol or DMSO-based alternatives
Key Findings
- •50% dimethylsulfoxide (DMSO) and 50% isopropylalcohol/isopropylmyristate showed the highest enhancement of lidocaine permeation through equine skin
- •Microneedle pretreatment significantly increased transdermal lidocaine delivery in a needle-length dependent manner
- •Chemical enhancers (alcohols, DMSO, propylene glycol) were more effective than PBS control for increasing skin permeability
- •The study demonstrates feasibility of improving topical anesthetic delivery through equine skin using both chemical and physical enhancement methods